1. Field of the Invention
This invention relates to apparatus and method for indexing and accurately registering a selected one of a plurality of deposition masks between a substrate and a source and more particularly to apparatus having a carriage assembly for indexing a selected mask from a plurality of masks adapted to be supported thereon between a substrate and a source and a gantry means which supports a substrate relative to the carriage assembly. The carriage assembly is utilized for indexing a selected mask from a plurality of masks between a substrate and a source in a vacuum deposition system.
2. Description of the Prior Art
It is known in the prior art to form thin film magnetic transducers by use of a stepped mask and vapor deposition techniques. Examples of thin film transducers so produced are disclosed in Gibson U.S. Pat. Nos. 4,191,983 and 4,143,458, which are assigned to the assignee of the present invention.
In fabrication of thin film magnetic transducers, it is common to form a pair of magnetic pole piece layers having deposited coils forming a coil winding therebetween and the two pole pieces which may have one or more layers per pole piece, having an interim gap formed therebetween. The gap is utilized for a transducing gap adapted to be positioned adjacent a recording media. In fabrication of the pole piece layers and one or more winding layers, any one of several techniques can be used in order to precisely control the width, length, depth and registration of the various layers relative to the prior deposited and post deposited layers. Typical of a magnetic transducer formed using such technique is that disclosed in U.S. Pat. No. 3,867,868 to Lazzari.
It is also known in the art to form a multi-track thin film magnetic transducer having a plurality of vapor deposited thin film transducers formed of a pair of magnetic pole pieces and windings therebetween. Typical of such transducers are those disclosed in U.S. Pat. No. 4,092,688 to Nomura et al.
In the fabrication of the thin film magnetic transducers disclosed by the above-referenced Patents, it is known in the art to utilize a mask for controling the pattern of deposited material onto a substrate during a deposition process.
One known prior art apparatus for forming thin film magnetic transducers of a plurality of vapor deposited layers utilizes a mask support assembly having a plurality of aligned apertures each of which support a mask having a predetermined pattern formed therein. In fabrication of the thin film magnetic transducers, it is necessary to carry out the vapor deposition in a vacuum chamber and to include apparatus which is adapted to transport the mask support assembly having the mask thereon which is located between a vapor deposition source and a substrate to index the mask support assembly to position a selected mask from a plurality of masks adjacent a substrate and between the source and the substrate and to precisely index a mask to the substrate. In fabricating thin film magnetic transducers, using the known apparatus it is necessary that precise indexing occur between the mask and the substrate so that proper registration and positioning of single or multiple deposited layers can be precisely established and controlled.
Other known techniques for fabricating thin film magnetic transducers include applying layers of preselected materials onto a substrate by use of known vacuum deposition, sputtering, plating, or chemical vapor deposition and then to selectively remove portions of the so formed layer by use of photo-etching techniques. In use of photo-etching techniques, the photo-resist material is coated onto the metallic thin film formed on the substrate through vapor deposition or plating processes. The photo-resist material is developed to form a photo-resist with a predetermined pattern wherein portions of the thin film layer to be removed are exposed and subjected to a chemical etching solution resulting in each layer of material in the thin film produced transducer having a preselected length, width, and depth in geometrical shape as determined by the photo-resist pattern formed thereon. One such method is disclosed in U.S. Pat. No. 3,891,995 to Hanazono et al.
A variation of this use of a photo-resist layer may include applying a layer of photo-resist material onto a substrate and forming apertures through the layer corresponding to areas to be plated. If an electroplating process is to be used, a layer of conductive material underlies the photo-resist layer and is used as a cathode in the plating process. If an electroless plating process is used, the layer of conductive material may be eliminated.
Another known technique for forming a thin film magnetic transducer is disclosed in U.S. Pat. No. 3,766,640 to Hahn. It utilizes magnetically permeable foil having grooves and a predetermined pattern formed therein which is adapted to receive deposited insulator and conductor material therein and which results in the foil member acting as both a portion of the magnetic transducer and as a pattern which determines the geometrical shape, width, and depth of the deposited layers.
Another known technique utilizes plating through a mask with a conductive material to form plated layers of magnetic insulating and conductive materials which define a plated layer magnetic transducer.